1. Field of the Invention
The present invention relates to a driving control method of a tire testing machine for performing a test while changing a slippage ratio of a tire with respect to a simulated road surface and a tire testing machine.
2. Description of the Related Art
Conventionally, there is a tire testing machine capable of rotating a tire shaft (a spindle shaft) to which a tire is installed by a tire driving electric motor and also rotating a drive drum having a simulated road surface with which the tire is brought into contact by an electric motor for the simulated road surface which is different from the tire driving electric motor described in U.S. Pat. No. 6,584,835.
In this tire testing machine, since the rotation number of the tire (speed of the tire) is differentiated from the rotation number of the drive drum (speed of the drive drum) in a state that the tire is in contact with the simulated road surface, it is possible to perform various tests of the tire while allowing the tire to slip on the simulated road surface.
In the test, by adjusting a difference between the speed of the tire and the speed of the drive drum, it is possible to change a degree of slippage of the tire with respect to the simulated road surface, that is, a slippage ratio.
However, at the time of adjusting the speed of the tire and the speed of the drive drum so that the slippage ratio is a desired value (at the time of change in the slippage ratio), when a surface state of the tire (a state of a tread), a contacting situation of the tire with respect to the simulated road surface or the like is changed, there is sometimes a case where an abnormal load change is given to the tire driving electric motor on the side of rotating the tire. According to circumstances, there is a fear that stick slip is caused and excessive loads are imposed on the tire testing machine.